In the 1920s and 1930s engineer/scientist/inventor E.F. Northup conducted extensive experiments using electromagnetic guns to launch projectiles. "Zero to Eighty" is a fictionalized account of those experiments, culminating in a trip to the Moon in a rocket given its initial boost by a huge electromagnetic cannon. The book is fully illustrated by photos and diagrams and contains an thorough technical appendix.
"The Moon Conquerors" by R.H. Romans, first published in 1930, was one of the first science fiction novels to describe a spacecraft given its initial launch boost by an electromagnetic gun.